15.3. Check of the unilateral vacuum valve

When checking the unilateral valve, the valve has to be in a vacuum hose.


  1. Remove a vacuum hose.

The unilateral valve is pressed in a vacuum hose in a certain situation.

  1. The vacuum pump check functioning of the unilateral valve.
Connection of the vacuum pump Criteria
From the vacuum amplifier of brakes Vacuum is created and keeps
From an inlet collector (In) Vacuum is not created

If the unilateral valve is faulty, replace it together with a vacuum hose.